Catheters are often used for performing continuous bladder irrigation. The most popular type of catheter used is a Foley indwelling or retention catheter that uses an inflatable balloon at the end being inserted into the bladder. See for example, U.S. Pat. No. 4,335,723 to Patel. For the Foley catheter a separate inflation tube adjacent to the main catheter tube or circumferential about the main catheter tube is used to inflate the balloon portion inside the bladder.
Urinary catheters bypass the normal bladder process of storing urine, and for releasing the urine by using the bladder detrusor muscle. Catheters can be a necessary tool to open the bladder to allow urination when patients have trouble urinating. A catheter can be a lifesaving tool since an uncontrolled buildup of urine can cause serious medical problems including renal(kidney) failure and death.
FIG. 1A shows a prior art indwelling Foley type catheter 1 with a balloon tipped end 3 adjacent to an interior bladder portion 12 adjacent to the urethra(neck) 14 of the bladder 10. Catheter 1 also includes a longitudinal tube portion 5 having both a main catheter line with output end 9 and a balloon inflation line 6 that feeds to an exterior valve port 7. FIG. 1B represents a cross-section of a portion inside of the urethra lining 14 having a catheter tube 5 inside the inner walls 15 thereof. A standard catheter tube 5 can have a wall thickness of approximately {fraction (1/16)} of an inch, with an outer diameter of approximately ¼ inch and a hollow inner diameter of approximately ⅛ of an inch. Along the inner wall 6 of the catheter tube 5 can be a fluid fill line 8 that is formed/located about the main drainage tube(lumen) portion 4 of the catheter tube 5. Although popular, these catheters have many problems.
In the prior art devices that use these typical catheters 5, the urethra passage 15 in the urethra always remains open to a uncontrolled, involuntary drip/drain urination whether the patient is in need of urinating or not. Thus, the typical catheter tube 5 is not capable of collapsing, and instead forces the urethra passage 15 to be maintained in a substantially open state.
The extra balloon inflation line 8 which could also be placed between 15 and 16, can also further restrict the diameter of the main catheter line thus reducing bladder drainage rate when needed. Additionally, the extra balloon inflation line 8 can require a larger insertion space diameter in the urethra passage 15 for being inserted into the bladder 10. Additionally, the Foley catheter must be stiff to be introduced into the bladder, and thus stretches the urethra 14 while being used.
The constant stretching of the passage 15 in the urethra 14 by the non-collapsible catheter tube 5 can be so painful in some patients that its' continued use cannot be tolerated. The continuous stretching of the urethra 14 can also produce urethritis and/or urinary tract infections. Often patients may need medications, sedation and sometimes narcotics to ease extremely painful bladder spasms and urethral discomfort that can develop from using the Folely catheter.
Various types of catheters have been proposed but still fail to overcome the problems of the Foley Catheter. See for example, U.S. Pat. No.: 5,183,464 to Dubrul et al.; U.S. Pat. No. 5,735,831 to Johnson et al. and U.S. Pat. No. 6,096,013 to Hakky et al. Each of these patents generally require inflatable portions or retainers having similar problems.
Catheters have also been known to cause other types of problems. Struvite crystal encrustation is the effect of stagnated urine in the neck of the bladder when using a catheter. In the face of an indwelling catheter, urine can pool at the neck of the bladder, and the pooled urine can shift from a normal acidic pH factor to an abnormal alkaline pH level of 10 or more while it stagnates. Urine shifts to an ammonia state where struvite crystals can precipitate and enlarge on the indwelling catheter. Struvite crystals have sharp, jagged edges which can seriously lacerate the urethral lining when the conventional catheter is removed. This bloody situation is not only excruciatingly painful but can lead to deadly infections. This situation can occur as the bladder loses its natural ability to cyclically flush itself in the face of an indwelling catheter. Bladder wall thickening has also be observed in long-term catheterizations and may be a result of the increasing pH levels.
Urinary tract infections can occur as the urine stagnates and shifts from its normal, acidic antibiotic property through the pH spectrum. Pooled urine that can occur in the neck of the bladder around the Foley balloon and beneath the indwelling catheter can be a natural breeding ground for microbes which can migrate in the body.
Bladder spasms can also occur with an indwelling catheter which causes the bladder to cease its normal cycle of filling and flushing. A dynamic functioning system is converted to a static state with a catheter, and painful bladder spasms can occur. Bladder atone can also occur where short term or more permanent loss of natural bladder functions occurs by using a catheter.
It is also generally well known in medical circles that a human body's primary defense mechanism against urinary tract infections and the other problems listed above is the process known as “wash-out”, where it is advantageous to allow a bladder to normally fill up and be released periodically at one time(all at once) rather than in an uncontrolled drip fashion that would occur with using a traditional catheter. See Cecil, Textbook of Medicine, Saunders Co. 18th Edition, Page 866, 1988; and Kunin editorial, New England Journal of Medicine, Vol. 319, No. 6. 1988.
Various catheter type instruments and procedures have been used for draining bladders of patients in hospitals. These instruments and procedures have evolved from constant (non-cycling) drip drainage through painfully inserted catheters by siphoning, suction and various types of awkward manually externally controlled cycling apparatus and procedures. Fundamental to an effective, safe, and appropriate device and method is allowing the bladder to fill reasonably and then draining it without a suction pump and without allowing build-up or entry of infectious contaminants in the drainage system.
U.S Pat. Nos. 2,602,448 and 2,860,636 use siphons in combination with reservoirs to provide cyclic draining of the bladder and pressure release is controlled by raising the height of the device on a bedside tree. These devices are subject to distortion by shifting and turning of the patient and are unreliable (can compromise safety) and restrict patients.
U.S. Pat. No. 3,598,124, describes a siphon leg controlled by attaching a catheter to a bedside tree at predetermined heights, to vary the pressure to drain the bladder with a flutter valve to break the siphon action of the system once the bladder has drained.
U.S. Pat. No. 4,230,102, describes a device for the draining of a bladder in which a T-joint has been placed on a catheter and has a pressure membrane attached thereto in a large casing for actuating a pressure switch which in turn actuates an electric motor driving a gear train and cam. A cam follower is spring loaded to clamp the catheter for two minute cycles upon actuation by the pressure switch to drain the bladder. These types of devices, can be expensive, bulky and positions an electricity source close to the catheter and the patient.
U.S. Pat. No. 4,424,058, describes a spring-return valve in conjunction with a siphon-release orifice to prevent both excessive suction and urine from remaining in the system after drainage. A problem with this system was that the restoring force of the spring increased with distance of travel from a closed position. The valve is unsatisfactory because it closed again as soon as the urine fluid pressure dropped off, thus causing fluid to remain trapped in the bladder to stagnate with further elapsed time. Only a full bladder would open it, sometimes at an uncomfortably high (and potentially unsafe) pressure, and then it closed too soon to allow complete drainage unless overridden by the patient bearing down heavily on the lower abdomen. Also, the tube positioning provided a situation for retention of fluid in the system.
U.S. Pat. Nos. 4,865,588 and 5,114,412 to Flinchbaugh, the inventor of the subject invention, describe “magnetic bladder cycler”, title, that requires a “magnet” sliding within a passageway to close a valve port and may use springs and the like, for enhancement. These devices must be added on as, or after, someone is catheterized and is mounted external the catheter. These devices use components substantially larger than a standard diameter of a catheter, thus taking up more space, is more obtrusive, more labor intensive.
None of the proposed patented devices and techniques described above solve all the problems with catheters that are listed above.